Seat support with adjustable height

ABSTRACT

An adjustable, telescoping seat support that allows the height of a bicycle seat to be adjusted to a number of seat height positions safely while bicycle is in motion. An elongated tubular seat post is clamped to a bicycle frame in a stationary position. A bicycle seat is attached to an end of a seat holder that is slidably positioned internal to the stationary tubular seat post. A coil spring provides an extending force on the tubular seat post and the tubular seat holder such that the seat support is capable of extending to a raised seat position and compressing to a lowered seat position. The seat is locked into raised and lowered seat positions by a plunger locking portion that is attached to the elongated tubular seat post and which remains at a fixed position relative to the seat for all seat height positions.

FIELD OF THE INVENTION

This invention relates generally to seat supports for vehicles. More particularly, it relates to adjustable height seat supports for bicycles.

BACKGROUND ART

Virtually all bicycles have adjustable seat posts for adjusting the bicycle seat to the rider's desired position. Generally, seat posts slide inside the upright seat post receiving shaft of the bicycle frame and are locked into position with a clamp. It is essential to fix the seat in the proper position, in which maximum pedal leverage and energy efficiency are attained. Lower positions place excessive stress on the knees, and higher positions cause the rider to rock from side to side to reach the bottom of the pedal stroke, causing lower back strain.

Experienced bicycle riders change their body position based on terrain and road configuration, and often need additional seat heights for their different positions. For example, on steep descents, the rider needs a lower center of gravity to keep the back of the bicycle on the ground. Currently, when reaching a hill, the rider must stop the bicycle, loosen a clamp, change the seat height, and then tighten the clamp. This process is repeated whenever a seat height change is required. In addition to being time consuming changing the seat height adds unnecessary and disruptive breaks to the ride.

In the U.S. Pat. No. 5,382,039, issued to Hawker, a spring-loaded seat support is described. The seat support disclosed by Hawker is adaptable to a bicycle frame and allows the bicycle seat to move up or down. However, the seat support does not provide a way to position and lock a bicycle seat into up or down positions, but rather serves as a shock absorbing seat support.

U.S. Pat. No. 510,993, issued to Riess, describes a spring-loaded seat support mechanism used to raise a seat from an initial depressed position. Before mounting the bicycle, the rider must manually adjust the seat to the lower position. The seat then automatically rises to the preferred height when the rider exerts pressure on the seat. Because the seat mechanism only works in one direction, it is not very useful for riders needing to raise and lower the seat without stopping the bicycle.

U.S. Pat. No. 2,644,504, issued to Vick, discloses a bicycle seat adjusting device that enables a rider to adjust the seat in both directions while riding. The device is relatively large, has many working parts and would be difficult to manufacture or fix. In addition, the device requires a polygonal seat post, rather than a standard cylindical seat post.

An adjustable seat support that is capable of adjusting a seat height while a bicycle is in motion has been described in U.S. Pat. No. 4,150,851, issued to Cienfuegos. The seat support described is not readily transferable from one bicycle to another because the mechanism for adjusting the seat height is an integral part of the bicycle frame itself. In a later patent issued to Cienfuegos. U.S. Pat. No. 5,044,592, this problem is overcome with an indent seat replacement unit that consolidates all of the parts of the seat support. However, this design places the locking and positioning portion of the seat support at a position near the horizontal portion of the bicycle frame. Mountain bicycles are designed with low frames and long seat posts, such that there is significant distance between the horizontal portion of the bicycle frame and the bicycle seat. A locking and positioning portion of a seat support system attached near the horizontal frame portion of the bicycle can be very difficult for the rider to reach while the bicycle is in motion and may cause the rider to lose balance while attempting to change the seat position. Further, since the locking and positioning mechanism changes its location relative to the rider with each new seat position, the rider will have to search for location of the locking and positioning mechanism while riding, again making the seat adjustment procedure unsafe. Also, the seat support device described in U.S. Pat No. 5,044,592 extends far into the upright seat post receiving shaft of the bicycle frame, which is not possible with all bicycle frame designs.

None of the prior art devices meets the requirements of adaptability, portabiity, and ease of use, wherein the seat support has a locking and positioning portion that is independent of the bicycle frame and remains in a consant, easily reachable position relative to the bicycle seat. Therefore, there is still need for a commercially viable option that satisfies the stated requirements.

U.S. Pat. No. 6,202,971 issued to Duncan. This device external slide can interfere with the bike frame under certain height conditions. Also it is more costly to manufacture than the proposed design

OBJECTS AND ADVANTAGES

Accordingly, it is a primary object of the present invention to provide an adjustable, telescoping seat support with a slidable, positioning seat holder that moves up and down in a tubular seat post that is fixed to a bicycle frame. A bicycle seat that is attached to the slidable, positioning seat holder is adjusted and locked in various height positions by a locking mechanism positioned substantially close to the attached bicycle seat. The present invention is well adapted for mountain bicycles, in which the seat is substantially higher than a horizontal cross bar portion of the bicycle frame.

It is a further object of the invention to provide an adjustable seat support that is not an integral part of the bicycle frame and that can easily be transferred from one bicycle to another.

It is an additional object of the invention to provide an adjustable seat support with a small number of predetermined seat height positions, where the rider can switch quickly and easily between the predetermined seat height positions while riding.

It is another object of the present invention to provide a simple and adjustable seat support. Wherein all of the adjustable and moving parts of the seat support are external to the bicycle frame, making repairs and maintenance to the seat support easier and less expensive.

It is a further object of the present invention to provide a seat support that is small and compact and that needs to be inserted only a short distance into the upright seat post receiving shaft of the bicycle frame in order to be safely secured to the bicycle frame.

Lastly, it is an object of the present invention to provide an adjustable seat support for bicycles that is readily adapted to most standard mountain bicycle frames.

SUMMARY

These objects and advantages are attained by providing an adjustable, telescoping seat support for attaching a seat, wherein an elongated tubular seat holder slidably moves up and down inside an elongated tubular seat post. A positioning and locking portion are configured on the tubular seat holder.

The telescoping action of the seat support is preferably provided by a coil spring positioned inside the tubular seat holder which provides an extending force on the inner stationary seat post and the tubular seat holder such that they tend to extend in a telescoping fashion in the absence of a compressing force or a locking mechanism. A downward force applied to the elongated seat holder through an attached seat, wherein the downward force is sufficient to overcome the extending force of the spring, will lower the seat position. The position of the attached seat can then be fixed in a preferred position with a lock. Releasing the lock will allow the seat to rise due to the extending force provided by the spring.

In the most preferred embodiment of the current invention, the locking and positioning portion of the seat support is a plunger locking and positioning portion. In the plunger locking and positioning portion, there is a plunger attached to the seat post in a direction substantially normal to the outer wall of the elongated tubular seat post, and which extends into a plunger hole in the seat support. The seat support has several plunger receptacles on the outer wall for receiving the plunger at different seat heights and locking the seat into a plurality of seat height positions. Preferably, the plunger is a spring-actuated plunger such that when the plunger is pulled in an outward direction, the seat holder is capable of sliding up or down inside of the elongated tubular seat post. Releasing the plunger then allows it to fit into one of the plunger receptacles and thus locks the seat into a new position.

In the most preferred embodiment of the seat support, the locking and positioning portion also includes a positioning stop that extends from an inner wall of the elongated seat holder and fits into an elongated slot grooved in the outer surface of the elongated tubular seat post and extending up and down the seat post in the elongated direction. The positioning stop and the slot serve to limit the rotational position of the tubular seat holder between seat height positions during adjustment, and serve to define the upper and lower limit of the seat height adjustments. In a particular embodiment, the seat support is configured to have two plunger receptacles that correspond to these upper and lower limits.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a side view of a preferred embodiment of the adjustable, telescoping seat support of the present invention, in the highest position.

FIG. 1B is a side view of a preferred embodiment of the adjustable, telescoping seat support of the present invention, in the lowest position.

FIG. 2A is a side cross-sectional view of the seat post member.

FIG. 2B is a top view of the seat post member.

FIG. 3 is a cross-sectional view of the seat support member.

FIG. 4 is a side cross-sectional view of the plunger housing and movable plunger of the present invention, with the movable plunger in the locking position.

DETAILED DESCRIPTION

Although the following detailed description contains many specifics for the purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Accordingly, the following preferred embodiment of the invention is set forth without any loss of generality to, and without imposing limitations upon, the claimed invention.

A preferred embodiment of the invention is shown in FIGS. 1A and B. A telescoping adjustable seat 14 is positioned between a vehicle frame and a seat for adjusting the height of the seat above the vehicle frame. In this embodiment, only two heights are possible, but any number of heights may be accommodated by the present invention. FIG. 1A shows seat support 14 in its highest position, and FIG. 1B shows seat support 14 in its lowest position.

Seat support 14 is formed from an elongated seat holder member 7 positioned inside an elongated seat post member 1. The elongated seat holder member 7 is tubular post member. Seat holder member 7 holds the seat and inserts into seat post member 1. A first spring stop is fixed inside seat post member 1 substantially near the end. In the embodiment of FIGS. 1A-1B, having seat end 14 closed provides the spring stop. Attached to seat holder member 7 is seat attaching means 8. In FIGS. 1A-1B, seat attaching means 8 is shown as a screw hole; a screw is inserted through this hole and into a seat to attach the seat to seat attaching means 8. Any other attaching means may be used, and attaching means 8 can also be a separate structure fixed to seat holder member 7. Seat post member 1 also has a frame end 17 for inserting into a vehicle frame. Seat post member 1 is clamped into a vehicle frame and remains fixed with respect to the vehicle frame while seat holder member 7 moves to raise and lower the seat.

A coil spring member 9 is positioned outside seat holder member 7 between the end of members 1 and 7. Coil spring member 9 acts to push seat holder member 7 and seat post member 1 away from each other, thereby raising the seat. When the seat is raised, seat post member 7 is said to move in the elongation direction. The stiffness of coil spring member 9 is such that, for any extension of the spring, a rider can easily compress the spring by sitting on the seat. When the seat is lowered, seat post member 7 is said to be moved in a compression direction. In the seat support device of the current invention, in the absence of a downward force, coil spring member 9 exerts a force on seat post member 1 that is sufficient to extend seat support member 7 in the elongation direction and thus raise the seat.

In the preferred embodiment of the invention the seat is attached to seat support member 7 a coil spring member 9 is between 1 and 7 that extends the seat upward. Therefore coil spring member 9 acts as shock absorber when the rider is sitting on the seat. The design can include a nut located above the coil spring member 9 that can change the compression rate of the spring to adjust for different weight riders or differ suspension rates. Rotation between 1 and 7 will be prevented by either keyway on item 1 and pin 13 on seat support member 7 or the area between 1 and 7 to be non-cylindrical.

Seat support 14 fixes the seat in a plurality of seat height positions with movable plunger 10. Movable plunger 10 is movably fixed to seat post member 1 at a plunger hole 3. Seat support member 7 also contains a plurality of longitudinally spaced plunger receptacles 6. In the preferred embodiment, plunger receptacles 4 and 6 are holes. When movable plunger 10 is positioned through both plunger hole 11 and one of plunger receptacles 4 or 6, seat holder member 7 is locked in position. This is the locking position of movable plunger 10, shown in FIG. 1A. Movable plunger 10 is fixed to seat post member 1 by plunger hole 11. Movable plunger 10 extends out of both ends of plunger hole 11. A plunger coil spring 12 is positioned inside plunger hole 11, between the back of plunger hole 11 and plunger stop member 10. Plunger coil spring 12 acts to force plunger 10 through plunger hole 11 and into plunger receptacles 4 or 6, i.e. into its locking position. In its releasing position, movable plunger 10 is removed from plunger receptacle 4 or 6. Movable plunger 10 is forced into its releasing position using a manually operable means. In the embodiment of FIGS. 1A-1B, the manually operable means is a handle 16 mounted on movable plunger 10. Many other manually operable means may be imagined, for example, a lever, a handle knob, or cable attached to movable plunger 10.

The preferred embodiment of seat support member 14 also contains a means for fixing the rotational position of seat holder member 7 during height adjustment. Seat post member 1 has a slot 2 extending a portion of its length as shown in FIGS. 2. The distance between two ends of slot 2 is between 0.1 and 8 inches. A pin 13 is rigidly fixed to seat holder member 7 and positioned to slide inside slot 2. In addition to limiting the rotational position of seat holder member 7, slot 2 and pin 13 also provide stop means for defining the maximum and minimum seat height positions. When pin 13 slides to the bottom of slot 2 or plunger receptacle 6, seat holder member 7 cannot go lower without breaking pin 13 Similarly, maximum height is reached when pin 13 reaches the top of slot 2 or plunger receptacle 4. Maximum seat height position is between 6 and 25 inches above the frame end 17, and the minimum seat height position is between 1 and 24 inches above the frame end 17.

In the preferred embodiment of the invention there are only two seat height positions corresponding to the maximum and minimum seat height positions. To lower the seat, the rider retracts plunger 10 from plunger receptacle 11. The rider's weight forces the seat to drop until plunger 10 hits the bottom of slot 2. The rider releases plunger 10 into its extended position, and seat holder member 7 is locked in position. To raise the seat, the rider shifts his weight to the pedals and retracts plunger 10. Coil spring member 9 forces seat holder member 7 away from seat post member 1 until pin 10 hits the top of slot 2. The rider then releases plunger 10 into plunger receptacle 11 and safely rests his weight back on the seat. When multiple heights are desired, the rider will need to keep a portion of his weight on the seat to stop the seat movement at the desired height intermediate between the uppermost and lowermost heights. He then releases plunger 10 and moves the seat slightly until plunger 10 fits into an intermediate plunger receptacle 4.

It will be clear to one skilled in the art that the above embodiment may be altered in many ways without departing from the scope of the invention. Also the spring may be configured with a dampening portion to reduce the rate at which the seat is raised from a lower to a higher position. Accordingly, the scope of the invention should be determined by the following claims and their legal equivalents. 

What is claimed is:
 1. An adjustable, telescoping seat support for adjusting a bicycle seat above a bicycle frame to a plurality of seat height positions, said adjustable, telescoping seat support comprising: a) an elongated seat holder member with an internal seat holder member, a hollow exterior portion, a seat end, and an open post end, said seat holder having attaching means for attaching to said bicycle seat; b) an elongated seat post member with an elongated inner seat post member and having a holder end slidably positioned inside said open post end of said elongated seat post member and a frame end, said frame end for attaching to said bicycle frame; c) means for providing an extending force to said elongated seat holder member and said elongated seat post member wherein said means for providing an extending force is positioned substantially inside said hollow interior portion of said elongated seat holder member and wherein said adjustable, telescoping seat support is capable of extending in an elongation direction to a maximum seat height position and collapsing in a compression direction to a minimum seat height position; and d) means for fixing said seat at said plurality of seat height positions wherein said means for fixing said seat at said plurality of seat height positions is attached to said elongated seat holder member and remains at a constant distance from said seat end in all of said plurality of seat height positions.
 2. The adjustable, telescoping seat support of claim 1 wherein said elongated seat holder member and said elongated seat post member are tubular post members.
 3. The adjustable, telescoping seat support of claim 1 wherein said means for providing an extending force to said elongated seat holder member and said elongated seat post member comprises: a) a coil spring member with a fit end and a second end, wherein said coil spring member is positioned over said exterior portion of said elongated seat holder member, such that said coil spring expands in said elongation direction and compresses in said compression direction; b) a first spring stop positioned within said seat holder member, wherein said first spring stop is in communication with said first end of said coil spring member; and c) a second spring stop positioned near said holder end of said seat post member, wherein said second spring stop is in communication with said second end of said coil spring member; thereby providing said extending force to said elongated seat holder member and said elongated seat post member.
 4. The adjustable, telescoping seat support of claim 1 wherein said means for fixing said seat at said plurality of seat height positions comprises: a) a plunger hole through said outer seat holder member wall into said hollow interior portion of said elongated seat holder member substantially near said post end, b) a plurality of plunger receptacles in said outer seat post member wall of said elongated seat post member corresponding to said plurality of seat height positions; c) a movable plunger sized to penetrate said plunger hole, wherein said movable plunger is capable of being moved to an outward releasing position and allowing said elongated seat holder member to be slidably moved in said elongation direction and said compression direction, and wherein said movable plunger is capable of being moved to an inward locking position with said movable plunger received in one of said plurality of plunger receptacles; and d) a locking mechanism for holding said movable plunger in said locking position.
 5. The adjustable, telescoping seat support of claim 4 wherein said locking mechanism comprises: a) a plunger housing having an open front end and an open back end, said front end rigidly mounted to said elongated seat holder member, said movable plunger movably mounted in said plunger housing; b) a plunger stop member rigidly mounted on said movable plunger, c) a plunger spring mounted in said plunger housing, said plunger spring positioned between said plunger stop member and said back end of said plunger housing for biasing said movable plunger toward said plunger hole in said elongated seat holder member, and d) manually operable means for retracting said movable plunger from said plunger receptacles in said elongated seat post member.
 6. The adjustable, telescoping seat support of claim 5 wherein said manually operable means is selected from the group consisting of a handle knob, a cable, and a lever.
 7. The adjustable, telescoping seat support of claim 4 further comprising: a) a slot with a first slot end and a second slot end positioned in said outer seat post member wall of said elongated seat post member, wherein said slot extend in said elongation direction and said compression direction; and b) a pin rigidly fixed to said hollow interior portion of said elongated seat holder member, said pin passing into said slot and sliding between said first end of said slot and said second end of said slot defining a range of seat height positions between said maximum seat height position and said minimum seat height position.
 8. The adjustable, telescoping seat support of claim 7 wherein said maximum seat height position is between 6 and 25 inches above said frame end and said minimum seat height position is between 1 and 15 inches above said frame end.
 9. The adjustable, telescoping seat support of claim 7 wherein the distance between said first end of said slot and said second end of said slot is between 0.1 and 8 inches.
 10. The adjustable, telescoping seat support of claim 2 wherein said frame end of said elongated seat post member is sized for fitting into a standard-diameter bicycle frame. 